CVE-2024-50130

netfilter: bpf: must hold reference on net namespace

State: Published
Severity: 7.8 High
Published: Nov 5, 2024
Updated: Aug 5, 2026
Reserved: Oct 21, 2024

Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: bpf: must hold reference on net namespace

BUG: KASAN: slab-use-after-free in __nf_unregister_net_hook+0x640/0x6b0 Read of size 8 at addr ffff8880106fe400 by task repro/72= bpf_nf_link_release+0xda/0x1e0 bpf_link_free+0x139/0x2d0 bpf_link_release+0x68/0x80 __fput+0x414/0xb60

Eric says: It seems that bpf was able to defer the __nf_unregister_net_hook() after exit()/close() time. Perhaps a netns reference is missing, because the netns has been dismantled/freed already. bpf_nf_link_attach() does : link->net = net; But I do not see a reference being taken on net.

Add such a reference and release it after hook unreg. Note that I was unable to get syzbot reproducer to work, so I do not know if this resolves this splat.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
LinuxLinux	84601d6ee68ae820dec97450934797046d62db4b to before f41bd93b3e0508edc7ba820357f949071dcc0accAffected 84601d6ee68ae820dec97450934797046d62db4b to before d0d7939543a1b3bb93af9a18d258a774daf8f162Affected 84601d6ee68ae820dec97450934797046d62db4b to before 1230fe7ad3974f7bf6c78901473e039b34d4fb1fAffected
LinuxLinux	6.4Affected before 6.4Not affected 6.6.59 through 6.6.Not affected 6.11.6 through 6.11.Not affected 6.12 and laterNot affected

References

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